Chlorine dioxide is a highly active chemical which has been widely used in a variety of processes and especially in disinfecting, sterilizing and bactericidal applications. Due to the unstable nature of gaseous chlorine dioxide when compressed, it is commonly prepared on site rather than having it placed in a container and shipping the container for usage at a site when and where needed. Liquid chlorine dioxide is considered to be very hazardous and is generally avoided.
The prior art discloses numerous procedures and generators for the preparation of chlorine dioxide. A partial listing of these are as follows:
______________________________________ U.S. Pat. No. Inventor Issued ______________________________________ 2,323,594 Hampel July 5, 1943 2,436,134 Aston February 7, 1948 2,484,402 Day et al October 11, 1948 4,081,520 Swindells March 28, 1978 4,250,144 Rategan February 10, 1981 4,247,531 Hicks January 27, 1981 4,590,057 Hicks May 20, 1986 4,861,514 Hutchings August 29, 1989 ______________________________________
All current commercial processes for generation of chlorine dioxide involve methods for combining sodium chlorate or sodium chlorite with acids or oxidizing agents in aqueous systems. The chlorine dioxide produced is isolated as an aqueous solution with concentrations varying from a few parts per million to over 9,000 parts per million. The process leading to this latter high concentration is an exception, and involves a recirculating loop to add new chlorine dioxide values to solutions already containing freshly generated chlorine dioxide.
U.S. Pat. No. 2,678,922 prepares an aqueous solution of chlorine dioxide and flushes the chlorine dioxide from the solution with air. The chlorine dioxide-air stream is passed through liquid chlorine to provide a liquid chlorine/chlorine dioxide solution. The only other non-aqueous solutions of chlorine dioxide of which I am aware are U.S. Pat. Nos. 3,056,270 and 3,084,995 in which chlorine dioxide gas is dissolved in liquid carbon dioxide. The latter reference states that it has been proposed to prepare chlorine dioxide in carbon tetrachloride but this has not proven to be successful due to the slight solubility of chlorine dioxide and because of spontaneous decomposition.
Furthermore, the use of organic materials with chlorine dioxide is generally avoided. Hampel does report the reaction of aqueous chlorate solutions with aqueous solutions of aldehydes to produce chlorine dioxide. Aston reports the "unexpected" reactions of organic acid anhydrides with aqueous solutions of chlorates to produce chlorine dioxide. The Merck Index, Tenth Edition, 1983 provides several references to the preparation of chlorine dioxide but provides the italicized warning "reacts violently with organic materials."
Thus, despite the interest in chlorine dioxide and the numerous methods of generating chlorine dioxide, the preparation and use of chlorine dioxide in a water-immiscible phase has not been disclosed. In fact, the prior art very strongly teaches away from such a preparation.